1. Field of the Disclosure
The disclosure concerns a fan impeller with a base plate and a number of fan impeller blades fastened to the base plate, the fan impeller blades being substantially arranged perpendicularly to the base plate and forming a substantially radial arrangement in which each fan impeller blade has a front edge arranged radially outwardly and substantially perpendicular to the base plate, a rear edge arranged radially inwardly and substantially perpendicular to the base plate, an outer surface arranged on the delivery side of the fan impeller and an outer surface arranged on the intake side of the fan impeller.
2. Related Technology
Fan impellers are generally known from the prior art and are used to circulate air. Fan impellers are known in a wide variety of forms, for example, fan impellers with propeller-like blades or with blade-like vanes are known. One problem in fan impellers known from the prior art is that solid and/or liquid particles present in the circulated air can deposit on the vanes of the fan impeller, which leads to soiling of the fan impeller. Undesired distribution of solid and/or liquid particles can also occur from the known fan impellers.
A particular problem is circulation of solid and/or liquid particles, especially in the form of grease particles, when the fan impeller is arranged within a cooking appliance. The fan impeller is generally arranged in a cooking appliance in a fan compartment separated from the cooking space by an air baffle, draws in air from the cooking space and diverts it radially to the enclosing walls in order to create air flow within the cooking appliance from the cooking space into the fan compartment and back again to the cooking space. A heating device or also a heat exchanger is often arranged around the fan impeller so that circulated air is also guided past this heating device or this heat exchanger in order to be heated. During a cooking process grease particles present in the circulated air can then also be guided to the heating device, where they can be burned, which can lead to a reduction in food quality and an odor burden. This is a particular problem if the air is permanently circulated within the cooking appliance by the fan impeller, in which case the solid and/or liquid particles are continuously kept in the gas volume by the circulating flow.
In order to reduce depositing of solid and/or liquid particles circulated by the fan impeller within a cooking appliance, is a device is known from DE 42 06 846 C2 that includes an impact surface or a separation ring around the fan impeller on which a gas flow prevailing in the gas volume occurs, in which case the solid and/or liquid particles are at least partially separated on impact and can go to a first bypass area.
A fan impeller with a number of radially arranged blades that protrude essentially parallel to the axis of rotation of the fan impeller from a support plate or base plate facing the housing wall of the cooking appliance is also known from DE 43 074 05 C2 in which baffles are arranged at least between some of the blades near the support disk, but with a spacing from it, whose radial outside edges are essentially flush with the outside periphery of the fan impeller, the radial inner edges lie at a spacing from the axis of rotation of the fan impeller and form a nozzle device with the support disk and the two adjacent blades to create a gas stream near the support plate directed radially outward.
A fan impeller is known from U.S. Pat. No. 1,688,345 in which at least one elevation extending away from the base plate is arranged on the outer surface of at least one part of the fan blades.
However, a shortcoming in the devices known from the prior art is that the efficiency of the fan impeller is reduced by the additional devices surrounding the fan impeller or arranged in the fan impeller, since the additional devices represent an obstacle to flow for the circulated air.